1. Technical Field
The present disclosure relates to an electrosurgical system and method and, more particularly, to an electrosurgical generator configured to dynamically control energy output.
2. Background of Related Art
Electrosurgery involves application of high radio frequency electrical current to a surgical site to cut, seal, ablate, or coagulate tissue. In monopolar electrosurgery, a source or active electrode delivers radio frequency energy from the electrosurgical generator to the tissue and a return electrode carries the current back to the generator. In monopolar electrosurgery, the source electrode is typically part of a surgical instrument held by the surgeon and applied to the tissue to be treated. A patient return electrode is placed remotely from the active electrode to carry the current back to the generator.
In bipolar electrosurgery, a hand-held instrument typically carries two electrodes, e.g., electrosurgical forceps. One of the electrodes of the hand-held instrument functions as the active electrode and the other as the return electrode. The return electrode is placed in close proximity to the active (i.e., current supplying) electrode such that an electrical circuit is formed between the two electrodes. In this manner, the applied electrical current is limited to the body tissue positioned between the two electrodes.
Conventional electrosurgical generators include a high voltage direct current power supply connected to a radio frequency (RF) output stage that converts DC energy generated by the power supply into RF energy. The power supply includes an output filter which substantially eliminates undesirable frequencies (e.g., noise) from the DC energy and stores large amounts of energy. Rapid tissue desiccation during the application of RF energy creates a potential for patient burn hazards due to excess energy dosage at the tissue site when the power source fails to rapidly alter the supplied energy dosage in response with dynamic changes in tissue impedance. Rising tissue impedance levels caused by desiccation unload the energy source and sustain the energy delivered to the tissue due to the large amount of stored energy in the output filter.